Western Digital WD9000 Pascal Microengine

Western Digital is now best known as a disk drive manufacturer, but
their origin was as a semiconductor company. At one time Western
Digital was the leading manufacturer of calculator chips. Western
Digital also developed the first single-chip UART, in conjunction with
DEC, and their other popular computer-related products included the 177x,
179x, and 279x floppy disk controllers.

In the mid-1970s, Western Digital designed an NMOS microcoded 16-bit
processor chipset for the DEC LSI-11. With different microcode, and an
instruction set that was similar to but not binary-compatible with the
PDP-11, the chipset was offered as the WD16, and used by
Alpha Micro in S-100 bus systems.

When UCSD Pascal started becoming popular, Western Digital developed a
set of microcode to directly interpret p-code. The Pascal Microengine
was made available in several forms: